Patent GB-1396911-A (GB)
Title: Manufacture of box blanks
IPC: B31B50/16
Filed: 1972-05-30
Abstract: 1396911 Making box blanks FMC CORP 30 May 1972 [2 June 1971] 25126/72 Heading B4B [Also in Division B6] Apparatus for making box blanks comprises means for unwinding a web of material from a parent roll, for cutting the web to width, for making longitudinal scores on the web, for making transverse scores by means of a die press which forms cornerpieces between successive blanks and for knocking out the cornerpieces and so separating the blanks. Rupturable tabs are provided in the cuts made by the press so that the blanks remain connected in strip form till eventually separated. Unwinding and slitting.-The roll 50 is mounted on a stand 42 and knife 56 on pivoted arms 58 cuts the roll to strips of the appropriate width. The stand is mounted on rolls 39 for movement with respect to the knife and a hand wheel 356 adjusts the knife position. Web tension.-The cut web passes through uncurling rolls 66 to a dancer frame 70 which maintains the web tension. The web passes round rolls 120, 122 pivotable about-108, and a gear segment on the pivot engages a pinion mounted on the shaft of a potentiometer so that as the shaft is turned the voltage to a motor 102 driving a drive roll 90 for the web is correspondingly varied and the web feed adjusted. Shearing and scoring.-Cutting wheels 168, 170 enable any damaged edge of the roll to the removed, wheel 170 removing the edge from the first strip WS and wheel 168 removing the opposite edge from the last strip to be cut from roll 50. Longitudinal scorew lines LS are produced by scoring wheels 172, 174 and a rule die 176 mounted on the upper press platen cuts the web transversely at T and scores it at T.S. Waste removal.-Plungers 182 are moved downwardly by flexible cable connections from the press so that the corner portions C are removed and the rupturable tabs broken. This mechanism is adjustable towards and away from the press according to the blank length. Drive.-A main motor drives a shaft (202, Fig. 3, not shown) carrying cams oprating switches to provide the correct sequence of operation of the various mechanisms. A clutch and brake (234, Fig. 3) cause intermittent feed of the web via a lower draw roll 248, Fig. 2. As stated above, roll 50 is driven by a separate motor 102 and is braked by a disc brake 51. Stopping switches are tripped when the knife 56 approaches the inner end of the roll 50 and if the web tension reaches a predetermined figure. Die Press.-The crosshead 166 is reciprocated from the main motor 184, Fig. 3, by a belt driven shaft 192, a clutch brake 282, a shaft 284 and a speed reducer 286. A transverse shaft 288 carries cams 310, 312 that reciprocate links 314, 316 carrying the crosshead. The gap between the platens can be adjusted by a worm and worm-wheel 550, 536, Fig. 7D. To accommodate platens of different sizes reinforced channels 692, Fig. 20 can be positioned with either their larger or small end uppermost or with their webs horizontal (Figs. 19, 21, not shown). Platens.-The rules for scoring and cutting are mounted in wooden plates and the lower platen has resilient strips of urethane so that that plate can move slightly to a position parallel with the top platen. Web guides.-These guides are adjustable to take different sized blanks. Modifications.-Two blanks can pass through the machine side-by-side to form a box and lid therefor by duplication of the various mechanism. The die press could be replaced by rules mounted on a roll so that the web is able to move continuously.